Rogers, his research team from the University of Illinois at Urbana-Champaign, and colleagues at Northwestern University and beyond have developed a liquid crystal display (LCD) tattoo that does more than look and sound cool—it monitors your health.

“It’s kind of the next-generation wearable technology—technology that by virtue of its intimate contact with the skin could provide clinical-quality data,” Rogers says in an Inside Science articleabout the tech.

The LCD tattoo consists of 3,600 liquid crystals, each just half a millimeter square, on a thin and flexible material.

The tattoo works like a mood ring—its liquid crystals change color with changes in body temperature, which indicate differences in blood flow, skin hydration, and heart rate, according to the article.

“That color difference will allow you to be able to map your blood flow, different veins, and tell you about your cardiac health and different physiological things in your body,” says Anthony Banks, an engineer at the University of Illinois.

Hear more about the tech from the scientists themselves in the Inside Science video below.

Users can slap on the tattoo, wear it for two weeks, and then snap a smartphone picture of the worn tattoo. An accompanying smartphone app allows users to swiftly translate the picture into a health report.

“We can determine skin hydration. We can measure lots of electrical signals associated with activity in the brain, the heart, the skeletal muscles,” Rogers says in the article.

The ultimate idea is that the patch can provide preventative health monitoring.

“If one’s health can be monitored 24/7 and it can tell you to see a doctor before something bad happens, that’s a huge savings, not only in money, but saving one’s life,” Northwestern University engineer Yonggang Huang says in the article.

“These results provide the first examples of ‘epidermal’ photonic sensors,” Rogers says in a Northwestern University press release. “This technology significantly expands the range of functionality in skin-mounted devices beyond that possible with electronics alone.”